Lace tail Tetra tail fungus?

Hello Friends, my Tetra has had a swimming bladder problem I believe for a year or so, haven’t been able to figure that problem out but have given up hope, he sinks in the rear and must keep forward movement to stay level and not sink, I have treated for every disease know and switched foods and don’t feed dry food. The problem as of late with her is a fungus, so I though, on her tail fin which look like a jelly and adds to her sinking problem, the first time this happened I treated with API All in one with no response so I simple scraped it off with a blade and treated with salt baths. Now it’s back again after a few months, I believe it’s coming from her tail rubbing the gravel while sleeping, she must keep wagging her tail to stay afloat while sleeping. But I have treated her with API primafix thinking is a fungus but still doesn’t touch it, the 30 gal. tanks perimeters are fine and it’s a well established tank with healthy fish and an algae eater that does a great job of cleaning. Water changes are weekly 20% with charcoal filters running. Any ideas would be appreciated, thank, William

Problems like that are not uncommon on "veil" or "lace" finned fish. I am not referring to bladder issues but to difficulty swimming, moving, resting in place (as in 'sleeping'), etc. with the long finnage.
It takes extra energy to perform normal life while carrying all those draggy fins, which are not even fully supported properly by fin rays as in a normal fish. Yes, I did say a normal fish. Veil and lace-fin fish are not normal.
On top of that, the long fins drag onto surfaces, get torn and damaged, and that provides entrance to potential secondary infections that a normal fish would not have. Further, it is irresistible to nippy fish, exacerbating the issues.
So, I am not sure what to suggest, just that one must realize what is going on with the fish and why. I guess this is just my (strong) opinion, but I do believe it is based on fact. Sorry, I don't know how else to state it.

Thanks Francisco, ya, I realize that there is nothing I can do about the swimming defect and I believe you are correct on the assumption that she picked the growth up from some sort of damage or dragging. I’m trying to figure out how to treat the growth, it is a jell like substance not cotton, don’t know if it’s a fungus, bacteria or some kind of growth, It appears rather fast and get the size it is in about a week or 10 days and that’s about it. Right now I’m treating with a anti fungal medication API Primafix but not reducing it, anything else to try?